The present invention relates generally to a waste water pump with an impeller.
Waste water pumps, which can be designed as submersible pumps, serve for pumping away sewage water and waste water. Such waste water often contains solid matter. Conventional pumps, as a rule, are provided with a single-channel or a multi-channel impeller for delivering the waste water. Such pumps are known, for example, from EP 1 300 594 B1 and WO 2011/079892.
The solid matter contained in the waste waters can lead to a blockage of the impeller. In particular, it is problematic that the solid matter can collect in an impeller side chamber on the outer side of the impeller and then can lead to a blockage of the impeller.
A pump is known from GB 2 310 252, with which a thread is formed in the sealing gap at the suction port of the impeller, by way of which thread contamination is to be moved out of the gap. However, a settling of contamination in the impeller side chamber can no longer be securely prevented even with this design, since too large a pressure difference exists between the pressure side and suction side.